(1) Field of the Invention
The present invention relates to a pair of parallel jaw pliers having a reinforced construction that centers the force distribution in the component parts of the pliers when in use. In particular, the present invention relates to a pair of parallel jaw pliers having a simplified construction with few component parts, where the component parts are constructed with reinforcing elements and are configured to center forces distributed through the component parts during use of the pliers.
(2) Description of the Related Art
Many various types of parallel jaw pliers have been developed in the prior art. The prior art pliers are constructed so that opposed jaw faces or surfaces of the pliers remain substantially parallel to each other as the jaws are closed and opened. To maintain the parallel orientation of the jaw surfaces, prior art parallel jaw pliers are typically constructed of three members. A first member has a handle at one end and a jaw surface at the opposite end. Aa second member has a second jaw surface formed thereon, and is connected with the first member in a manner that enables the second jaw surface to remain substantially parallel to the first jaw surface as the second member is moved toward and away from the first member. A third member has the second handle formed thereon, and is connected with the second member to cause the jaw surface of the second member to move toward and away from the jaw surface of the first member in response to the two handles being moved toward and away from each other, respectively. Examples of these prior art plier structures are disclosed in the U.S. patents of Russell U.S. Pat. No. 82,994; Melchers U.S. Pat. No. 2,399,497; and Ly U.S. Pat. No. 2,836,999.
A disadvantage commonly found in prior art parallel jaw pliers of the type described above is that their construction is not centered in a plane that extends perpendicular through the planes of the opposed jaw surfaces of the pliers. The connections between the opposed jaw members of the prior art pliers are made between opposite sides of the jaw members and are not centered in the jaw members themselves. This construction often produces a lateral force component in the opposed jaw members that tends to separate the jaw members laterally from each other as the gripping force exerted by the jaw members is increased. This lateral force component detracts from the total gripping force that may be exerted on the object gripped between the jaws, and after prolonged use of the pliers could eventually lead to the failure of one or more of the component parts of the pliers.
Prior art parallel jaw pliers have been developed specifically constructed to center the gripping force through the centers of the component parts of the pliers. An example of this type of prior art parallel jaw pliers is disclosed in the U.S. patent of Peck U.S. Pat. No. 1,677,365. These types of prior art pliers also typically employed three members. A first member has a handle at one end and a first jaw surface at its opposite end. A second member has a second jaw surface formed thereon, and is connected in some fashion to the first member to enable the second jaw surface to remain substantially parallel to the first jaw surface as it is moved toward and away from the first jaw surface. A third member has a second handle formed thereon and fork type projections formed at one end that extend around and are connected to opposite sides of the first and second members. This construction of prior art pliers tended to distribute forces exerted on the pliers through the centers of the component parts of the pliers and substantially eliminated the lateral forces exerted on the opposed jaw members of the pliers when in use. However, these types of pliers were often found to be disadvantaged in that their construction required the fork like projections to extend across the working area defined between the opposed jaw surfaces of the pliers. In these types of prior art pliers, the fork like projections often interfered with placement of the pliers over an object to be gripped by the pliers with the object positioned at the extreme rearward area between the opposed jaw surfaces. Positioning an object in this area would often be prevented by engagement of the fork like projections of the pliers against the object, resulting in the fork like projections exerting a gripping force against the object rather than the opposed jaw surfaces of the pliers.
The above types of prior art parallel jaw pliers are also often disadvantaged in that, because the pliers are constructed of several component parts, the dimensions of the parts are reduced so that the pliers can be easily hand held and operated with one hand. Reducing the dimensioning of the component parts of the pliers often resulted in reducing the strength of the connections between the component parts.
What is needed to overcome the disadvantages associated with prior art parallel jaw pliers is a pair of parallel jaw pliers that is constructed in such a way that the component parts of the pliers are kept to a minimum, that the working area defined between the opposed jaw surfaces of the pliers is not obstructed by any of the component parts of the pliers for all adjusted positions of the jaw surfaces relative to each other, and where the component parts of the pliers are constructed in such a way that the connections between component parts enable the parts to move in both pivoting and translatory movements relative to each other and are reinforced without appreciably increasing the size of the component parts of the pliers.